Chapter 2 section 3 – Flashcards
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What is a seismograph?
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A device that records ground movements caused by seismic waves as they move through Earth.
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How does a seismograph record seismic waves?
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Seismic waves cause a seismograph's drum to vibrate. But the suspended weight with the pen attached moves very little. Therefore, the pen stays in place and the records the drums vibrations.
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A seismograph records a strong earthquake and a weak earthquake. How would the seismograms for the two earthquakes compare?
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The bigger earthquake would show bigger, more jagged lines on the seismogram and the weaker quake would have shorter lines.
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What four instruments are used to monitor faults?
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Tiltmeters, creep meters, laser-ranging device, and GPS satellite.
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What changes does each instrument measure?
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Tiltmeter measures vertical movement.
Creep meter measures horizontal movement.
Laser-ranging device measures horizontal movements.
GPS satellite measures vertical and horizontal movements.
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What could an increasing tilt in the land surface indicate?
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It indicates a build up of stress in rock and could lead to an earthquake.
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What are three ways geologists use seismographic data?
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Mapping faults, monitoring changes along faults and trying to predict earthquakes.
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How do geologists use seismographic data to make maps of faults?
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Seismographs detect the reflected seismic waves and geologists use this data to map the length and depth of the fault.
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Why do geologists collect data on friction along the sides of faults?
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So they can try to predict the probability of a large earthquake.
